1. Field of the Invention
This invention generally relates to heat sinks for computer systems, and more particularly to a heat sink for a high energy consumption device, such as a central processing unit, which may be placed in close proximity to low power consumption components, such as memory chips.
2. Description of the Related Art
Computer systems such as workstations, personal computers, and portable computers may include components housed within an enclosure. Some components, such as central processing unit (devices) and memory chips, typically mount on circuit boards within the enclosure. Other components, such as circuit boards and disk drives, typically mount to a chassis of the computer system.
Only a limited amount of space exists within a computer enclosure. Computer systems may be designed to make the best use of the available space. Computer components need to be in close proximity to each other so that the best performance from the computer components may be obtained. However, having computer components in close proximity to each other may be problematic due to geometry and heat generation factors within the computer enclosure.
A computer component may function properly only when an operating temperature of the component is at or below a maximum operating temperature. In some instances, a package surface area of a component is too small to permit sufficient heat transfer from the package to keep the component at or below maximum operating temperatures using natural convection. Such a component requires additional cooling. If the temperature of a computer component exceeds the maximum operating temperature of the component, or if the temperature within the computer enclosure exceeds a maximum operating temperature, a reduction of computer performance may occur. Eventually, the components of the computer system may be permanently damaged or destroyed if the computer components or the computer system are operated at too hot a temperature.
Some computer components may be high power consumption devices. High power consumption devices typically generate large amounts of heat during use. Generally, high power consumption devices require cooling to function properly. The cooling of a high power consumption device may be accomplished by attaching a heat sink to the high power consumption device. The high power consumption device transfers heat to the heat sink, and the heat sink transfers the heat to the surroundings. One type of heat sink provides a thermal connection between a heat transfer surface of the high power consumption device and a convection cooled surface area of the heat sink. A cooling fan, or cooling fans, within the computer enclosure may provide forced convection to transfer heat from the heat sink to the surroundings if natural convection within the computer enclosure does not provide enough heat transfer to the surroundings. It is desirable to provide a heat sink for a high power consumption device that has a large heat transfer surface area. The heat sink should allow the device to operate at as low a temperature as possible.
One type of heat sink for a high power consumption device includes a base having a plurality of fins extending from an upper surface of the base. The base has a lower surface that generally corresponds to the principal heat transfer surface of the high power consumption device. The upper surface of the base typically has the same shape as the lower surface of the base. The fins provide extended heat transfer surface area for the heat sink.
Another type of heat sink for a high power consumption device is shown in U.S. Pat. No. 5,412,535, issued to Chao et al, and is incorporated by reference as if fully set forth herein. The heat sink comprises a base with a vertically mounted heat pipe connected to the base. The lower surface of the base thermally contacts the heat transfer surface of the high power consumption device. Horizontal fins extend from the heat pipe to increase the heat transfer surface area of the heat sink.
Some computer components, such as a collection of static random access memory (SRAM) units, may be low power consumption components. Low power consumption components may require heat sinks to keep the components functioning properly. A heat sink for a low power consumption component may be required if the component generates excessive heat during use, or if the component is placed near a high power consumption device. Individual heat sinks may be provided for individual low power consumption components, or one heat sink may be used to cool several low power consumption components.